The following description of background art may include insights, discoveries, understandings or disclosures, or associations together with disclosures not known to the relevant art prior to the present invention but provided by the invention. Some such contributions of the invention may be specifically pointed out below, whereas other such contributions of the invention will be apparent from their context.
The evolvement of communication technology, particularly IP-based (IP, Internet Protocol) communication technology and end user terminals, has enabled versatile communication possibilities and introduction of different services. More and more often services are implemented using an IP Multimedia
Subsystem IMS, such as an All-IP system standardized by the 3GPP, and employing an IP-based session control protocol, such as a SIP (Session Initiation Protocol) protocol. IMS provides multimedia services which are usually, although not necessarily, Internet-based services employing a packet protocol. SIP is an IETF defined application-layer control protocol which is not vertically integrated into a communications system but a tool to build a multimedia architecture.
In a multi-service architecture, a particular media (and enablers) can be used by a number of services. For example, IMS is a multi-service architecture that supports a number of services on a common set of enablers (an enabler is a procedure that fulfils a specific function) and uses the same access point name for different services and applications. Thus, means other than the media, access point name or enabler used is required to identify that a particular service is being requested or invoked. Although a need for a service identifier has been realized, no mechanism as to how to exploit service identifiers has been suggested.